mantovanello etal



Mar h 3 1964 e. MANTOVANELLO ETAL 3,127,333

SUSPENSION OF ANODIC CASINGS IN CELLS FOR THE UCTION OF ALUMINUMELECTROLYTIC PROD Filed March 23, 1959 4 Sheets-Sheet l March 31, 1964cs. MANTOVANELLO ETAL 3,127,338

SUSPENSION OF ANODIC CASINGS IN CELLS FOR THE ELECTROLYTIC PRODUCTION OFALUMINUM Filed March 23, 1959 4 Sheets-Sheet 2 FIG.5

' F|G.6 22 /& zz 9 6 0 x; e 0 i a n March 31, 1964 G. MANTOVANELLO ETAL3,127,338

SUSPENSION 0F ANODIC CASINGS IN CELLS FOR THE ELECTROLYTIC PRODUCTION OFALUMINUM Filed March 25, 1959 4 Sheets-Sheet 3 Z0 Z4 /X ,y f/ I 54 M raa H L, 9 .Z& 4 244, F|G.8 1'0 FIG.9 25 if 25 #25 24x March 31, 1 4 eMANTOVANELLO ETAL 7,

SUSPENSION OF ANODIC CASINGS IN' CELLS FOR THE ELECTROLYTIC PRODUCTIONOF ALUMINUM Filed March 23, 1959 FIG. IO

FIG."

FIG. I2

4 Sheets-Sheet 4 United States Patent SUSPENSIQN 0F ANUDIC CASENGS INCELLS FOR THE ELECTROLYTIC PRQDUCTIGN OF ALUMINUM Giovanni Mantovanello,Eolzano, and Silverio Bruni, Milan, Italy, assignors to MontecatiniSocieta Generals: per llndustria Mineraria c Chimica, Milan, Italy FiledMar. 23, 1959, Ser. No. 801,266 Claims priority, application Italy Mar.25, 1958 1 Claim. (ill. 2tl4--225) The present invention relates to anew type of suspension of the anodic casing for self-baking electrodesin cells for the electrolytic production of aluminum.

In particular this is an improvement to the recent types of electrolyticcells for the production of aluminum which are fitted with self-bakingelectrodes, e.g. of the Soederberg-Montecatini type, provided withvertical iron contact rods for feeding the electric current to theanode, and includes the types described in copending applications SerialNo. 480,509, filed January 7, 1955 now Patent No. 3,029,194; Serial No.551,679, filed December 7, 1955 now Patent No. 2,938,843; and Serial No.587,985, filed May 29, 1956 now Patent No. 2,952,592, all assigned tothe assignee of the present application.

The suspension system claimed herein can be applied to anodes having acircular or rectangular cross section as well as to those having arectangular cross section with rounded short sides. In such a suspensionsystem, the contact rods are firmly anchored to the baked portion of theanode and, therefore, exert also the function of a suspension member. Inthe store-mentioned types of cells the vertical iron contact rods areconnected by suitable clamps with the anodic beam, the ends of which aresupported by vertical screw jacks which render possible the verticalregulation of the anode.

The anodic beam of the electrolytic cell comprises one or more rigidlyconnected metallic beams. In the specific examples disclosed in thepresent specification reference is made to an anodic beam comprising twoelements. Obviously the scope of the present invention includes alsocells having one beam element or more than two beam elements. Hence thegeneric term anodic beam is used herein without being limited to anyparticular number of elements.

The anode of the cell is contained in a sheet-iron casing, suitablyreinforced by means of iron sections and destined to contain the crudeelectrodic paste and to protect the half-baked and baked portionsagainst atmosphreic oxidation. The anodic casing in general isterminated by a small anodic gas collecting ring for collecting theliberated anodic gas and the products formed by distillation of thepitch used as a binder for the anodic paste.

During normal running of the electrolytic cell the anodic casing shouldcover the electrode to the greatest extent possible without coming tooclose to the molten electrolytic bath, in order to avoid any possibilitythat iron may pollute the bath and, therefore, pollute the aluminumproduced.

To achieve these ends, the anodic casing must remain at a predeterminedand constant distance from the bath while the anode must be loweredregularly as carbon is continuously burnt by the oxygen developed at theanode from the electrolysis of alumina in the bath.

The anode therefore slides Within the casing which remains in astationary position.

For this reason, in cells as made heretofore the casing as well as thecontact rods in general have not been connected directly 'with theanodic beam. With the prior systems as used heretofore, the casing isusually connected with a special independent beam resting on supportscon- 3,127,338 Patented Mar. 31, 1964 nected with the ground. The casingis adjusted, by means of screw jacks or the like, at the desireddistance from the bath, which distance remains constant in practice, andthe electrode, pushed by the anodic beam through the contact rods,slides gradually down through the casing. 'In these prior devices theanodic beam is controlled by the vertical screw jacks as theelectrolytic combustion of the baked anode paste proceeds.

The suspension of the anodic casing on an independent supporting beaminvolves structural complications which all lead to the need forincreased horizontal and vertical space requirements for the anode, thusrendering more ditficult the accommodation of devices for mechanizingthe various operations for conducting the cell, such as, e.g. mechanizedcharging of the anode paste and of the alumina, tapping of the aluminumproduced, mechanized breaking of the crust. The necessity of mechanizingthose operations is particularly felt in high amperage cells, e.g. of100 ha. and more.

It is therefore an object of the present invention to provide animproved type of suspension for the anodic casing of an aluminumelectrolytic cell so as to maintain the anodic casing at a constantdistance from the electrolytic bath, while permitting the anode to beregularly lowered as necessary.

It is a further object of the invention to provide an improved type ofsuspension for the anodic casing of an aluminum electrolytic cell, whichsuspension is structurally simple in construction and which requires aminimum of space, thus rendering possible the automatic and mechanizedcharging of anode paste into the cell.

Still another object of the invention is to provide a type of suspensionfor the anodic casing of an aluminum electrolytic cell which blocks onlydownward movement of the casing, but which results in upward movement ofthe casing when the anode is lifted from a predetermined level.

According to the present invention these and other objects are achievedby connecting the casing to the anodic beam, to which the contact rodsare also secured, by means of a mechanical system having a variance ofone degree of freedom and which keeps the casing in a predeterminedposition while the beam is lowered in order to make up for anodeconsumption.

In this way the former types of supporting beams expressly destined forand attached to the casing can be dispensed with.

Of course, in both the known means of suspension and in that claimedherein, when the anode is lifted for working needs, such as variation ofinterpolar distance, the casing, owing to its considerable upward taper,is dragged upwards by the electrode. The guide stays of the casing slideWithin their guide holes to permit such upward movement, and blockage ofcasing movement occurs only for descent.

If, to make up for electrolytic combustion the anode in an apparatusaccording to the invention, is lowered by the amount by which it waspreviously raised, the casing returns to its predetermined position.

This connect-ion or suspension according to the invention preferablycomprises a mechanical system of which two basic types are describedherein; namely a funicular (rope) system and a rigid-lever system; thesetwo types operate on the same general principle though differing inconstruction.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following escription of specific embodimentsand modifications when read in connection with the accompanying drawingsin which the same numerals designate the same or corresponding partsthroughout the several figures, and in which:

FIG. 1 represents diagrammatically in elevation view one embodiment ofthe suspension system according to the invention, using ropes, chains orcables;

FIG. 2 represents the embodiment of FIG. 1 in plan view;

FIG. 3 represents diagrammatically in elevation view another embodimentof the suspension system according to the invention, using a rigid leversystem;

FIG. 4 represents the embodiment of FIG. 3 in plan view;

FIG. 5 is an enlarged detail of the suspension system of FIGS. 3 and 4;

FIG. 6 represents diagrammatically in elevation view another embodimentof a suspension system using rigid levers;

FIG. 7 is a plan view of the system according to FIG. 6;

FIG. 8 represents diagrammatically in elevation View anothermodification of a suspension system using rigid levers;

FIG. 9 is a plan view of the system according to FIG. 8;

FIG. 10 is an elevation view of still another embodiment of thesuspension system using a rigid lever system;

FIG. 11 is a plan view of the system according to FIG. 10;

FIG. 12 is an end view of the system according to FIG. 10;

FIG. 13 represents diagrammatically a detail of a modification of theembodiment of FIG. 6 in larger scale.

Although the drawings illustrate a type of anode having an elongatedrectangular section with rounded shorter sides, it is obvious and shouldbe understood that the present description also is intended to includerectangular or circular anodes.

In FIGS. 1 and 2 is illustrated diagramrnatically a connecting systemaccording to the invention utilizing metallic ropes or chains. Theanodic casing 2. is terminated by and is supported at its upperextremity by an angle iron or other type of suitable reinforcing element2a.

Four sturdy eye brackets 7 are fixedly attached to the upper corners ofthe casing 2, and the respective ends of four metallic cables or chains8 are secured to the brackets 7 by means of conventional pivot pins orgudgeons (not illustrated). The four cables or chains 8 respectivelypass through four sets of cooperating pairs of sheaves tor pulleys 9,1d, each sheave being pivoted horizontally on the anodic beam 11, untilthey reach two horizontal beams 51 to which the other ends of the cablesor chains are fixedly secured. The sheaves 10 of each pair 9, Iii arearranged so that each of their working circumferences is placedtangential to a vertical axis passing through the eye brackets 7, whilethe sheaves 9 are arranged so that each of their workingcircumierencesis tangential to a vertical axis passing through the upperfastening point 52 of the cable or chain to the beam 11.

The length of the metallic ropes or chains 8 is previously predeterminedand adjusted at a value corresponding to the desired position of theanodic casing 2. Then when the anodic beam 11 is lowered, the positionof the casing 2 remains fixed, since the length of the rope or chain 8is constant.

Rigid lever systems according to other embodiments of the invention areillustrated in FIGS. 3 to 13, and

these comprise systems of linked rigid members, which connect the anodiccasing 2 with the anodic beam 11 and operate to produce a result similarto the embodiment previously described with respect to FIGS. 1 and 2,

i so that the casing remains stationary when the beam 11 is lowered.

Four structural modifications of such systems of rigid linked membersare described and claimed as preferred embodiments of the presentinvention as follows:

FIGS. 3-5 illustrate diagrammatically, by way of example, one embodimentof the principle of a system for connecting the casing 2 to the beam bymeans of simple rigid levers, stay rods and struts.

As is best illustrated in FIG. 3, four eye brackets 12 are secured tothe four corners of the upper edge of the casing 2. Four stay rods 13are pivotally attached at 12a to the eye brackets 12. A nut 13a at theopposite and upper extremity of stay rods 113 permits adjustment of thelength of stay rods 13. A bushing 13!) is slidably mounted on rod 13 andis provided with a projecting boss. Four triangular levers 14, havingrespective legs 14a, 14b and 140, are pivotally mounted at 14] forrotating on respective ones of four horizontal journalling pivots 15which are welded or otherwise secured to the anodic beam 11. The threelegs 14a, 14b and Ma of each triangular lever 14 are fixed with respectto each other and at their vertices 14d, 14c and 14 form pivoting meansfor struts 16, bushings 1312 on stay rods 13 and journals 15,respectively.

Struts 16 are hingedly attached at their lower extremity 17 to a fixedbase 17a while at the other end they are pivotally attached to the lowervertex 14d of triangular levers 14. The length of the stay rods 13 isadjustable by threaded nut 13:: so that the vertical position of theanodic casing 2 with respect to beam 11 can be changed as desired.

Rod 13 slides together with nut 13a freely in bushing 13b to whichmember 14 is articulated at Me.

Thus, nut 13a limits the stroke of rod 13 and consequently of casing 2,only downwardly not upwardly. Therefore, once the position of nut 13a isadjusted, if the anodic beam 11 is lowered, the position of the casing 2remains substantially unvaried, while a cooperating rotation of thestays 13, struts 16 and triangular levers 14 takes place around theirrespective pivot joints. If the anodic beam 11 is lowered, bushing 13babuts against nut 13a, limiting the further lowering of easing 2, andthe rods 16 act as struts between triangle 14 and pivot joint 17.

In raising the beam 11 from a lowered position, rod 16 rotatescounterclockwise while arm 14a of triangular lever 14 rotates clockwise.Casing 2 is lifted only when the anode is lifted, and then stay rod 13with nut 13a attached thereto slides upward through bushing 13b. The nut13a limits only the downward stroke, but not the upward stroke of stayrod 13.

To lift the beam 11, while leaving the anode at a standstill, thecurrent carrying studs are utilized. For this purpose, the currentcarrying studs should be clamped to the casing and unclamped from thebeam 11. If on the contrary the anode is to be lifted, the studs remainclamped to the beam 11 and in that case they are not clamped to thecasing.

Example 1 By way of a numerical non-limiting example of actualdimensions, with a lowering of the beam 11 by 400 mm., the anodic casing2 remains fixed in practice by using a lever system corresponding tothat described above in connection with FIGS. 3 and 4, and having thefollowing dimensions.

Triangular lever 14:

Length of arm 14c mm 600 Length of arm 14b mm 535 Length of arm 14a mm271.6

Angle between the sides 14a and 14b (i.e. be-

tween the sides 535/ 271.6 mm.) degrees Length of strut 16 mm 1330Length of stay 13 mm 500 Obviously, the anodic casing 2 can also be keptfixed in practice by adopting other actual dimensions of the struts 16,stays 13 and triangular levers 14. For strokes or movements of theanodic beam 11 greater than 400 mm., the entire system can bere-dimensioned conveniently to suit the particular requirements.

FIGS. 6 and 7 illustrate a modification of the embodiment of thesuspension system in which the connection from the casing to the anodicbeam is by means of double rigid levers, rather than single triangularlevers as in the embodiment of FIGS. 3-5.

The system of FIGS. 6 and 7 is somewhat similar to the preceding oneillustrated in FIGS. 35, except that in lieu of the single triangularlevers 14, there is provided an assembly of two bell crank levers 18 and19, connected to each other by a linking lever 29. The bell crank levers18 and 19 are pivotally attached at 21 and 22 to the anodic beam 11. Asin the case with the embodiment according to FIGS. 3-5, the connectionto the casing 2 is completed by stay rods 13 and a bushing (notillustrated) corresponding to bushing 13b. The connection to the fixedbase 17:: is completed by struts 16 pivoted at 17. The length of thestay rods 13 is adjustable by means of a nut 1301 so that once adjustedthe anodic casing 2 remains in the desired position as the beam 11 islowered. As the anodic beam 11 is lowered, the casing 2 remains at astandstill because of the fact that the individual components of thelever system cooperate with each other so as to displace the stays 13,slidable in bushing 13b, in a direction oppo site to the loweringdirection movement of the anodic beam.

Example 2 By way of a numerical non-limiting example of actualdimensions, with a system according to FIGS. 6 and 7, and for strokes ofthe anodic beam 11 in the range of, for example, 400 mm., the casing 2remains fixed in practice with a system of levers having the followingdimensions:

Length of struts 16 mm 1061 Length of links 20 mm 385 Length of stay 13mm 500 Bell crank lever 19345 x 250 mm., angle 8040 Bell crank lever13250 x 355 mm., angle 90 It should be obvious that other dimensions ofthe elements of this system can also be used to keep the casing 2 at astandstill in practice. Also, with greater strokes of the anodic beam11, the system can be re-dimensioned accordingly to suit the conditions.

The embodiment according to FIGS. 8 and 9 is particularly suitable foranodes of great length, and comprises two pairs of stays 28, 29connected to the beam 11 by means of a bell crank lever 23 and a linkinglever 26.

The assembly of this embodiment comprises a strut 16, one end of whichis hingedly pivoted on a fixed base 1711 at 17, and the other end ispivotally connected with an angular or bell crank lever 23 which canrotate on a pivot 24 fixedly attached to anodic beam 11. The other endof lever 23 is slidingly connected by means of a bushing (similar to13b) to the stay rod 28. Stay rod 28 is pivotally hinged to casing 2 at28a, and another pair of stay rods 29 are similarly hinged at 2% to theanodic casing. A horizontal stay rod 25 joins the respective bushings13b (not shown in FIG. 8) located on each respective pair of stay rods28, 29, and a lever arm 26 joins the slidable bushing of rod 29 to apivot journal 27 which is fixedly attached to beam 11.

The four pairs of stays 28, 29 complete the connection between levers23, 26 and the casing 2. In this embodiment the casing is supported ateight points, four points being distributed on each side (28a, 29a, 29a,28a), and the distance between these connecting points are approximatelythe same on each of the two opposite longitudinal sides along the upperedge 30 of casing 2.

The suspension system illustrated in FIGS. -12 supports the casing fromthe anodic beam 11 by means of a system of rigid levers and stifftransmission members which are somewhat analogous in principle to thepreceding embodiments, but operates in planes which are perpendicular tothe two anodic beams instead of in planes parallel thereto, as in thepreceding embodiments.

In this embodiment the assembly comprises four struts 16, each havingone end hinged to a fixed base 17a at 17, and the other end of eachlever 16 is pivotally attached to levers 32 (FIGS. l1, 12). Each of thelevers 32 is fixedly secured, such as by a key, to the outwardlyextending terminal portion of a respective bar 31. Bars 31 are pivotallyjournalled in supports 34 which are fixedly attached to the anodic beam11. The inwardly extending end portion of each bar 31 is fixedlysecured, such as by a key, to respective levers 33. Stay rods 13' havingnuts 13a threaded on their lower extremities, are slidably connectedthrough holes in the upper angles 30 of casing 2. The upper ends of rods13' are pivotally suspended from the inner extending end portions ofbars 31.

The operation of the embodiment of FIGS. 1012 is analogous to that ofthe previous embodiments, in that if the beam 11 is lowered, thesuspension system coacts in such a manner as to leave the casing 2 fixedin a predetermined position.

Any of the types of connection illustrated in FIGS. 1-12 can be appliedfor suspension of any type of anode, such as rectangular, rectangularwith rounded short sides, circular, etc. Depending upon the length ofthe anode and the distance between the anode and the outer side wall ofthe electrolytic cell, one or the other of the illustrated suspensionsystems may be preferable.

The suspension system according to FIGS. 3 and 4 is particularlysuitable for rather short anodes which are disposed not too far awayfrom the cell wall. The suspension system illustrated in FIGS. 1 and 2,6 and 7, and 8 and 9 are best suited for long anodes, which arerelatively distant from the side wall of the cell, while the suspensionsystem of FIGS. 3 and 4 is best suited for short anodes close to thecell wall. The suspension system of FIGS. 1012 is well suited for anodesof any type.

By adjusting the nut 13a, the stays 13 or 13' which connect the anodiccasing 2 with the respective levers of any of the suspension systems of1-12 can be adjusted to any suitable length corresponding to the desiredposition or elevation of the casing 2 or, better to say, by means of thenut 13a it is possible to vary the maximum distance 146-43, that is, themaximum distance between the beam 11 and the casing. Stay rods 28, 29,and 13 and 13 are all similar in this respect. Thus, in a manneranalogous to the chain or cable system of FIGS. l-2, the position or"the casing 2 is maintained in position by means of the threadedlyadjustable stays 13, 13', 28, and 29.

FIG. 13 illustrates a modification of the suspension system of FIGS. 8and 9, but is also applicable to any of the suspension systems of FIGS.312. The end of the lever 23 is pivotally attached to a bushing 13bslidable on rod 28. A pair of sturdy helical springs 35 on each end ofthe bushing 13b retain the pivoted end of lever 23' and bushing 13bbetween the upper and lower nuts 13a. Consequently, if the anodic beam11 is lowered to follow the anode consumption, when the casing 2 isdragged downward, the springs 35 become tensioned or compressed therebyso as to bring the casing 2 slowly again back into the desired position.

It will be obvious to those skilled in the art, upon studying thisdisclosure, that devices according to our invention can be modified invarious respects and hence may be embodied in devices other than asparticularly illustrated and described herein, without departing fromthe essential features of our invention and within the scope of theclaim annexed hereto.

We claim:

In an apparatus for recovering metal by electrolysis in a fused bath,including a pot structure constituting a cathode, an anode of thecontinuous type, a casing for said anode mounted independently of saidpot structure for vertical movement relative thereto, a verticallymovable suspension beam above said casing, and contact rods suspendingsaid anode from said beam; a suspension system for supporting saidanodic casing from said beam and capable of maintaining said casingapproximately at a desired constant position of elevation relative tosaid pot structure during vertical displacements of said anode and ofsaid suspension beam, said system comprising mechanical linking meansfixedly attached at one connecting location thereof to said casing andat another connecting location thereof to a fixed location apart fromsaid beam, and guide means fixed to said beam and operably associatedwith said linking means so as to maintain said constant position of saidcasing and limit vertical movement of said beam to a maximumpredetermined distance equal to the maximum vertical distance betweensaid connecting locations of said linking means, said mechanical 10prising journal means fixedly attached to said ancdic beam and forming aconnection thereon for journalling said lever means at the third pivotpoint thereof.

References Cited in the file of this patent UNITED STATES PATENTS2,816,861 CasteX Dec. 17, 1957

